Summer Succotash With Marjoram

Name: Summer Succotash With Marjoram
Ingredients: 3 tablespoons butter; 3 tablespoons olive oil; 1 large onion, chopped; 1 red bell pepper, cut into 1/2-inch pieces; 1 green bell pepper, cut into 1/2-inch pieces; 1 garlic clove, minced; 2 cups fresh corn kernels (from about 3 ears); 2 medium-size zucchini, trimmed, cut into 3/4-inch pieces; 2 medium-size yellow crookneck squash, trimmed, cut into 3/4-inch pieces; 1 10-ounce package frozen baby lima beans, thawed; 4 tablespoons chopped fresh Italian parsley; 1 tablespoon chopped fresh marjoram